Tension device



July 19, 1938- R. H. LAWSON ET AL 2,124,001

TENSION DEVICE Filed June 12, 1956 F1C.Z.

2 l MBA/T025.-

503522712 LAM 0116 I/i YzLM/YLSMZTHJJE;

Patented July 19, 1 938 UNITED STATES PATENT OFFICE 2,124,001 Y i I TENSION DEVICE 1mm 11. Lawson and William L. Smith, 11.,

Pawtucket, R. 1., assignors to Hemphill Com- Pany, Central Falls, Massachusetts B. L, a corporation of justable and is designed tension once it has been manufacture, easily adto maintain a constant adjusted properly. It is a special purpose of this tension device to exert sage of'knots or slubs.

yarn and to maintain The tension device has been found to greatly improve fabric produced on multi-feed knitting machines and also allows the production of better plated fabrics as well as rendering better service in knitting machines of 1 all descriptions.

and particularly desirab chines, is not limited to This tension device, while developed in conjunction with knitting machines le for use in such maany single field in the textile arts, but has definite advantages which recommend it for use in tensioning yarn or filaments passing through all types of textile apparatus.

In the drawing:

Fig. 1 is an elevation of the tension device;

showing a simple form Fig. 2 is an elevation showing this tension device as seen from another angle;

Fig. '3 shows this same tension device, partly in section, and further illustrating the tensioning loop adjusted to give a different degree of tension Fig. 4 shows the same yarn tension device,

parts being omitted, but

illustrating a method of Fig. 6 illustrates this same tension device as seen from another view point; and

Figs. 7, 8 and 9 show details of the cleanin element and a manner of adjusting the same.

7 It is a special requirement of yarn tension devices as employed with knitting machines that the device may exert a very slight drag upon the yarn or filament passing therethrough and that this drag be exerted continuously, at as nearly a constant amount as is possible. Such tension devices must not be influenced by different speeds at which the yarn variations of speed of 8.

passes through them or by passing yarn. The adjustment state the amount of drag exerted should be positive, and once set, should remain at that amount without any appreciable change.

, previously the passage of knots or slubs has always had such an influence upon the action of the device that their efiect has been transferred through to the fabric being produced and thus the inability of the device properly to compensate for these inequalities problem in the knitting oi!v fine fabrics.

In overcoming the difllculties above outlined, we have found that an extremely light and sensitive tension device may be constructed by forming one of the yarn engaging elements as a loop of very thin spring-steel. This spring steel is obtainable in strips of varying widths and may be easily bent back upon itself in the form shown and when suitably secured to the other element of the tension device itself, can be employed to exert almost any reasonable drag upon a yarn passing between 'said loop and another yarn engaging element against which the loop presses the yarn or filament. This strip material is commercially obtainable down to a thickness of .001 of an inch and, of course. up to any thickness desired. For practical purposes about .003 of an inch would probably be a maximum limit insofar as ordinary knitting machines are concerned. The loop thus formed of this thin strip steel may be closed or opened and thus the degree of tension may be varied within definite limits.

The employment of such ultra-thin spring steel allows us to obtain an extremely .light tension and a constant one which would be practically impossible with any other tension means heretofore devised. A further advantage in the employment of the strip material bent upon itself to form a loop as shown is that this loop can move away from the'other yarn contacting element and further, in a direction in which the yarn itself is traveling. When a knob or slub or other imperfection is passing through the tension device this movement automatically prevents any jerk on the yarn and thus irons out the tensioning action into one that is extremely delicate but which does not vary throughout a degree which can be evident from imperfections in the fabric when it has been produced. We know of no other tension imposing means capable of exerting an extremely light drag upon a yarn and which is sensitive inthe respect noted so that the light tension necessary may be maintained at a substantially constant flgure.-

Referring to Figs. 1-4 a simple form of our device has been illustrated wherein an angular element I has a pair of porcelain or other guides has been an annoying thicknesses of 2andlthroughwhichayarnlpassesinadirection from left to right, Fig. 1. Said angular element has an extension 5 with an aperture 6 therein by means 01' which it is to be attached to the machine wherein employed in any suitable manner. Between the guides 2 and 3 said angular element is formed into a curved portion 1,

this portion 1 being one of the yarn engaging,

elements and constituting one part of said tension means against which the yarn itself is pressed by the upper portion of loop 8 formed 1 of very thin strip steel as above described. This loop 8 has been bent back upon itself and the two ends have been formed with holes therein through which a screw 9 having an adjusting thumb nut it passes to maintain said spring loop in position on the shank of angular element 1. A slider ll having turned edges which guide it upon element I is provided with an elongated slot I 2 which encompasses a screw 9. This slider ll may be moved lengthwise of element-l to vary the size of the loop as has been illustrated in Figs. 1 and 3 these figures showing the extreme positions. This adjustment may be facilitated by means of graduations I 2 on one of the members, preferably on stationary element I.

The adjustment herein described is effected by means of loosening thumb nut 10 'and moving slider II in either direction as desired and then tightening said thumb nut to fix said adjustment permanently. Skilled textile workers may be able to determine from the feel of the yarn running through the tension device when the ,proper adjustment has been reached, or it may be possible to use any of the known types of tension gauges whereby all devices on machines havthat a rotating element has been employed in opposition to the resilient loop whereby the tension device is rendered self-cleaning.- This tension means has a shank I with one end l5 provided for attaching to some support on the machine and the other end having a loop of thin spring steel is attached by means of screw ll, thumb nut It and slider l9 all in a manner similar to that described with respect to securing and adjusting loop 8, Fig. 1. 'About midway of the shank a porcelain guide 2| is inserted for passage of the yarn to be tensioned by means of loop l6 and cooperating roller 2|.

Figs. 7 and 8, this plate 24 may be swung,

througha limited arc so-that the'position of roller 2| may be varied whereby its parallel-engagement with loop It will be assured. Otherwise loop It might engage at one end of the roller and the yarn in working back and forth along the roller as it does to a slight 'extent would feed with varying amounts of tension. The slot The shank has been constructed having ears turned down at 22 in ear 23 is somewhat larger than the reduced end of roller 2 l to allow the adjustment which has been described. In effecting this adjustment the operator merely loosens screw 25, swings the plate 24 until the axis of roller 2| aligns properly with the face of loop It with which it engages, and then tightens screw 25 to maintain the adjustment permanently.

It is possible to adjust this loop in the same way loop I was adjusted and the function of roller 2| is to prevent a collection of lint or other foreign matter at the area wherethe yarn is drawn through between the loop and cooperating tensioning surface. A second porcelain guide is not employed in this form of the invention.

Either of these tension means is easy to thread and assures very light-starting tension in comparison to the drag exerted after the yarn or thread has started to run. As before stated tension may be extremely light without any noticeable fluctuation as knots and the like are passed through during operation of the device 'to which the tension means is attached. The weight of loops 8 and I6 is comparatively negligible and compared to other known tension devices, the inertia of the parts which must be moved as knots or other imperfections pass ofi'ers almost no resistance to changes of position. Due to the. peculiar action of the loop constructed of such ultra-thin material, the loop itself movesin the direction of the passing yarn to compensate the tendency for the yarn to jerk as it would on passage of impefections in other known tension. means. Very little wear occurs on the loop or on the roller and practically no tendency for the yarn to groove these elements is evident. While two particular forms of the tension means have been described in this case and the action of devices has been described relative to a knitting machine, it is not to be understood that the invention is in any way limited except by the scope of the appended claims.

We claim:

1 A yarn tension device including cooperating yarn engaging members between which a yarn is drawn, one of said members being formed as' a loop of relatively thin, resilient material and so disposed relatively to the other that it presses the yarn against the other, but moves away from it and with the yarn upon passage of'a knot or the like.

-2. A yarn tension device having opposed yarn engaging members, one member being formed as a loop of thin, strip spring steel and the other member being formed to present a non-resilient surface between which and said loop a yarn is to be guided, and means for adjusting the size of said loop. he thin metal being readily susceptible of such adjustment.

3. A yarn tension device as defined inclaim 2 wherein said adjusting means includes a slider with a slot therein and a clamping member passing through said slot for an adjusted position.

4; A yarn tension device having opposed yam engaging members, one member being formedas a loop of thin, resilient material and the other member comprising a roller.

5. A yarn tension device having opposed yarn engaging members, one member being formed as a loop of thin, strip spring steel and the opposed member comprising-a roller rotatable in bearings which maintain it parallel to the surface of said loop and means for adjusting one of said bearings to adjust the position of the roller.

retaining the slider in 6. A yarn tension device having opposed yarn engaging members one member being Iormed as a loop of thin strip spring steel and the other member being movable whereby lint is prevented from accumulating on either member.

I. A yarn tension device having opposed yam I engaging members, one member being formed as a loop of thin, strip spring steel, said loop being so disposed relatively to the passing yarn that deflection of the loop moves the yarn engaging surface of the same in the direction in which the yarn is passed.

8. A yarn tension device including two opposed tensioning members one of which is constructed as a closed loop of strip material less than .004 of an inch in thickness.

9. A yarn tension device including cooperating yarn engaging members between which a yarn is drawn, one of said members being formed as 58 a loop of relatively thin resilient material and so engaging members.

disposed relatively to the other that it presses the yarn against the other, but moves away from it and with the'yarn upon passage oi a knot or the like, and means for retaining said loop of resilient material so constructed and arranged as to allow adjustment oi the size of said loop.

10. A yarn tension device having opposed yarn one said member comprising a closed loop 0! thin, strip spring metal and retaining means for said loop movable to vary the size of said loop.

11. A yarn tension device having opposed yarn engaging members, one member being formed as a loop oi thin, strip spring metaland the other member being formed to present a surface between which and said loop a yarn is to be guided, and'means including a member for retaining said loop movable to vary the size thereof.

ROBERT E. LAWSON. WILLIAM L. SMITH. JR. 

